Process and apparatus for reclaiming waste products in the manufacture of wood-pulp.



H. K MOORE AND J. T. QUINN. PROCESS AND APPARATUS FOR RECLAIMAING WASTEPRODUCTS m THE MANUFACIUREOF WOOD PULP.

APPLICATION HLED HJB. 13. I918.

Patented Dec. 30, 1919.

HHHHHHHHHI- UNITED STATES PATENT orrron.

HUGH K. MOORE AND JOHN T. QUINN, OF BERLIN, NEW HAMPSHIRE, ASSIGNORS TOBROWN COMPANY, OF PORTLAND, MAINE, A. CORPORATION OF MAINE.

: PROCESS AND APPARATUS FOR RECLAIMING WASTE PRODO'C'IS IN THEMANUFACTURE OF WOOD-PULP,

To all whom it may concern:

Be it known that we, HUGH K. Moons and JOHN T. QUINN, citizens of theUnited States, residing at Berlin, in the county of Coos and State ofNew Hampshire, have invented new and useful Improvements in Processesand Apparatus for Reclaiming Waste Products in Y the Manufacture ofWood-Pulp, of which the following is a specification.

This invention has relation to the recovcry of the mineral or inor aniccontent of the liquor employed in the igestion of raw material in themanufacture of cellulose fiber, although it is capable of Wideapplication in various arts.

In order that the nature of the inven- .tion may be understood, we shalldescribe it particularly in relation to the manufacture of sulfate pulpor soda pulp, in which,

after the raw material has been subjected to a process of digestion, thefiber is separated from what is termed the black liquor", the lattercontaining various valuable inorganic products which it is desirablecontent recovered in its desired condition.

Said Letters Patent show how the principles of Stefans law may beapplied to the evaporation'of the water and the recovery of the sodafrom the blackliquor resulting from the so-called sulfate process. Thislaw'reduced to simple terms may be stated as follows: B. T. U. radiatedper square foot of radiating surface per. minute: 2.6 8X i0 (T -'"-T,)when T is the absolute temperature of the body which radiates heatand.T, is the absolute temperature of the body to whichheat is radiated. Itis evident that, if'one can reduce the amount of heat. required to beradiated, one will t a direct benefit due to maintaining a big eraverage temperature in the. radiating body which must necessarily losein temperature Specification of Letters Patent; Patented-Dec, 30, 1919;Application filed February 13, 1918. Serial No. 216,998. l

as it radiates heat. This increases the heat.

radiated in a given space of time from-the same surface area,- or, tostate it differently,

one can cause the radiation of a reater quantity of heat from a smallerra iatin eign fuel introduced into the furnace and by the combustionofthe combustible content of the black liquor, it having been found upto that time that the introduction of a foreign fuel, such as gas, oilor powdered or pulverized coal or coke, was necessary for the productionof the requisite radiant heat. It was the intention, as expressed in theLetters Patent referred to,

-- by the employment of a blast of air to atomize the fuel, and also bya blast of air or steam to atomize the lignin'or black liquor so as toreduce it to the finest ossible particles and thereby to increase t eevaporating and radiating surfaces of the particles of black liquor, butthis was done, as stated,

by pressure or bycontact with a blast of alr or steam external to theparticles themselves. liquor, at the time of its introduction into thefurnace, is in a high viscous state due to its preliminary partial e'vaoration and concentration, the particles t ereof when subjected to ablast of high velocity, are necessarily large, relatively speaking,because of their hlgh viscosity and great cohesive properties, and theyconsequently acquire a high velocity, due to the air blast, through thespace in which they were subjected to the radiant heat. Because of the.

rapidity with which these particles are projected'through the heatingspace, they are Inasmuch, however, 'as the black subjected in transitfor only a minute length of time to radiant heat, and, because of theirglobular or compact condltlon, they acquire ess heat by convection thanif they were sub-divided into small particles. Furthermore, because ofthe'relatively heavy weight ofthe relatively large particles thusatomized by a blast of air, their velocity is necessarily hio'hthroughout their travel. In particles of the same material, the inertiasistance of the air is as the square of the is as the cube of thediameter while the rediameters are approached, the resistance,

- due to the square of the diameter, overtakes and exceeds the inertia,which is as the cube of the diameter. Thus, as the diameter of theparticles is decreased, the resistance of the air rapidly decreases thevelocity thereof, and the distance which they travel. If thesub-division of the particles is continued, a particle may be obtainedso fine that, while it will start with an initial,

high velocity, this velocity will be almost instantly checked, with aresult that the particle might be said-to float inthe air. Furthermore,when the particles of relatively large size and heavy weight aresubjected to both'heat of radiation and heat of convection, although theperipheralportions of the particlesmayhave had the water evap-. .oratedtherefrom'andv the carbonaceous portions 'partiallycha'rred, there iscontamed in the middle of the particles a pasty mass through which jtheheat has not penetrated a loss of radiant. heat which might have beenobtained in the particles had they all been brought to a radiantconditionduring their flight from the nozzle to the floor, or

which might have been obtained if those which were brought to atemperature where they would radiate heat to a considerable extent intheir transit were possessed of a greater. radiating surface. a

' In the process and apparatus disclosed in the Letters Patentpreviously mentioned, the

means of sub-dividing these particles was, as previously Stated,entirely external. In carrying out said process, there were employed, inpractice, first, Various kinds ofv can be sub-divided to such an extentthat mechanical nozzles in which the centrifugal force of one portion ofthe liquor rotating in contact with another portion of the liquorrevolving in the opposite direction tended to strip the entire liquorinto, fine particles;

and, second, fiat nozzles designed to subdivide the liquorinto a sprayby a thin knife-like blast of airat high pressure and high velocity.These nozzles, while they did not meet'the optimum conditions, yet

' were sufficiently successful that the whole operation of an industrialplant was based upon their use. Nevertheless, as heretofore explained,though the particles produced by such nozzles were comparatively minutein r relation to drops, they were relativelv large in comparison withparticles which would be. practically all surface and no volume.

weenie Inasmuch as these particles were so relatively large, the heat ofconvection and what radiant heat would ordinarily come from the walls ofa furnace, sublimed soda salts, and burning particles of black liquor,were not sufficient to evaporate these particles in their entirety whilein transit, and they arrived at the furnace floor in a more or less wetor pasty condition and tended to smother the fire thereon. In order toovercome these difficulties, an extraneous source of heat had to besupplied, and it was derived from the combustion of powdered coal, oil,or. gas. In the use of gas, for example, the radiant particles werecomposed of illuminants, which, heated to a high temperature by theburning gases and also burning themselves, added enough additional heatso that the particles of liquor would reach the furnace fioor in acondition not to blanket the fire, and the operation therefore could becontinued. A plant, running successfully under these conditions, hasbeen operated for several years. 2

Inasmuch as the'blast of air,'in order to properly disintegrate thablack liquor, cannot practically be over 6/1000 of an inch in width, itwill be readilyseen that a slight wearing of theseair nozzles greatlreduces the efliciency-of the operation. Tliat is, as the air nozzle isgreater in width, the tendency .becomes greater to blow the black liquorin mass away r atherv than disintegrate or atomize it. In the so-calledsulfate proc- Y ess, the dry residue from the black liquor onevaporation contains somethin over 5,000-

B. T. .U. 'pengound. In the su fite process, the dry res ue containssomething over 6,000 B. T. U. per pound. If, then, 2 pounds of-blackliquor containing 50% water werethey will acquire a large part of theheat required for evaporation from the surroundinghot gases, the amountof radiant heat which will have to be added thereto may be very small.

The object of the present invention, in contra-distinction to theprocess disclosed in. said patent, is: first, to eliminate the necessityof using a foreign fuel for bringing about the combustion of theconcentrated or partially evaporated black liquor; second, to increasethe capacity of a furnace of a given size and also to prevent losses dueto the exterior radiation and conduction of heat from the furnace walls;third, to insure a greater evaporation of the Water contained in theparticles of black liquor during their transit by convected and radiantheat, there: by to bring about the charring and combusi tion of thecarbonaceous portions of the black liquor contained in the particleswhile in transit, and thus to furnish additional radiant heat for theeva oration of subsequent particles of the b ack liquor which have notreached the radiant sta e; fourth,

to reduce the weight of the partic esof black liquor and to increasetheir surface area,

' thereby to insure their heating by convec tion and to reduce thevelocity of their travel through the heated ases in the furnace; and,fifth, to insure t at the alkaline efiiuent of the furnace is maintainedhiglr in sodium sulfid. v

In explanation of the manner in which these objects are attained, weavail ourselves space it previously occupied; for example, a

pint of water, roughly speaking, when transformed into steam at 28inches vacuum, occupies 350 cubic feet or 21,000; times the space itoccupied as water. We may utilize both of these principles in securingthe desired results in the practice of our invention, by preheating theliquor to a high tern perature while maintaining it under pressuregreater than the vapor pressure at that temperature, and then liberatingit in a stream in a furnace, whereby we obtain a double explosiveefi'ect which dis'-- rupts the li%uor internally and disinte rates itinto the nest possible particles. 5 an illustration, let it be assumedthat the liquor is heated to a temperature of 350 F, while maintained ata pressure greater than its vapor pressure, and is then suddenlyliberated in the furnace in which there is (for example) a partialpressure corresponding to 28 inches of vacuum (for instance anatmosphere of 93-1/3% inert gas, and 0-2/3% steam) under theseconditions there would be an explosive action in-the liquor due to theinstant reduction in tem erature from 350 F.'to 212 F. at atmosphericressure, and the further reduction to 100 due to the partial vacuum.While it may now be possible or practical to store sufficient heat tochange al of the water of the black liquor into steam, it is practicalto raise the liquor to ,a sufiiciently high temperature while holding itunder great pressure, to cause the transformation of one-fourth or toone-third of such water into steam with the resultant explosive action.B generating a high explosive force in the liquor and injecting theliquor into the furnace, irres ective of a par: tial pressure therein-(whio may or may not exist, although we have reason to assume a partialpressure), the explosion which occurs causes the disintegration of theviscid material into minute particles, and thetearing aplart of thelignin or cementitious cement t ereof, so that, roughly speaking, theparticles are very light and are practically all surface. Consequently,although the particles start at high velocity in the furnace, theirvelocity is almost instantly checked and a large part thereof may besaid almost to float in the air, and hence not only is the waterevaporated, but the particles are charred, and the carbonaceous contentis charred and actually consumed by combustion while in transit, thusfurnishing a high degree of radiantheat for the following particles ofblack liquor. Under these conditions, we have eliminated the necessityof using a foreign fuel, as the combustion of the pombustible content ofthe black liquor in transit, and, as it reaches the furnace floor,furnishes-the heat of radiation and convection for the evaporation ofthe water content.

, In carrying out the invention, we may use 1 5 is a stora e receptaclefor finely pulverized salt ca e which connects through removablediaphragms 6 and pipes 7 with the agitator tank 4. The diaphragm 6 is removable and may be made of various sizes so that the salt cake, which isto be mixed with the liquor, shall correspond to the amount of liquorcoming from storage tank 1. From the mixer tank a the mixture is drawnthrough pipe 8 by a pump 9 and delivered through pipe 10, and T 11, pump12, by which said black liquor and salt cake are forced through pipe 13into coil 14 of the heater 15, and thence through the pipe 16 to headerpipe or manifold 17 having valves 18 leading to pi es 19 projected intothe furnace. The hea or 17 is also, by means of an extension 20,connected with pump 21 and pipe 22 (having a check valve 221, ifdesired) to T 11. Steam is introduced into the chamber in the heaterthrough a pipe 23 leading from a steam main not shown. The

drip from the heater 15 is delivered through pipe 24 to a trap 25 fromwhich the condensed water is discharged. The pipe 19 from the manifold17 is projected into the door of the furnace 26 which heats the boiler27. The particles of the black liquor, which is atomized into a sprayindicated at 28, are largely consumed while in transit, while largerunconsumed but more or less charred particles are deposited on the pipe29 on the sloping floor of the furnace where they are completelyconsumed. The consumed gases and fine solid particles which float in thefurnace gases are carried through the lines of boiler 27 to a stack 281through fan 291, and pipe 30, Where they v are either switched directlyto the atmosj phere through the extension 31 of pipe 30, or into a.Oottrell precipitator 32 where the particles are precipitated into ahopper 33 while the gases escape to the atmosphere through pipe 34. Thesmelted efiiuent is delivered from the furnace'through spout 35 intoagitator tank 36. As described, in the previous Letters Patent,hereinbefore referred to, air at 3 to 5 pounds positive pressure isdelivered through pipe 37 into the fire chamber below the spray tosupport the combustion. It may also be stated that the black liquor,which runs into the storage tank 1, may be obtainedin a partiallyevaporated and concentrated viscous condition from the evaporatingsystem A, A, here represented conventionally as twoefi'ect.

The operation may be brie-fly described as follows:

After the liquor has been mixed with a finely divided salt cake inmixing tank 4, it is necessar to keep the liquid in very rapidcirculation to maintain the salt cake in suspension,'for it must berealized that, after the liquor' has been concentrated to about a 55%solution, it will not then dissolve the requisite amount of salt cake.Consequently all means for feeding the black liquor employed after thesalt cake" has been'added must be such as'to prevent the salt cake fromsettling. This is accomplished in the present case by keeping it at highvelocity during the remainder of its travel, and by passing it throughthe coil in the heater, wherein the centrifugal force-of the liquor intraversing the coil and its constant change indirection keep the mixturewell stirred so that it becomes rapidly heated and does not stick to thewall of the coil or polymerize by prolonged contact with a given heatsurface. Pump 9 and pump 12 are shown in the drawing in place ofatwo-stage or threestage pump, in order that the operation may be moreclearly depicted. In practice, however, pumps 9 and 12 are preferablybuilt as two-stage or three-stage pumps.

Pump 9, in delivering the liquor through pipe 10 into pump 12, builds upthe required pressure; first, to maintain the velocity in the liquorcoil Id, and, second, to maintain a pressure far above the corre-.sponding vaporizing pressure of the liquid at the temperature to whichthe steam entheaters tering at pipe 23 would heat it. For instance, ifwe desired to heat the liquor to 335 R, we should maintain at all timeson manifoldjli' as shown, goes through a pipe 20 to pump 21, thencethrough pipe 22, into the T 11, between pumps 9 and 12, or between thefirst and second stageof a twostage pump. The drawing here illustratesonly one of the manymethods in which this operation can be accomplished.For instance, pump 21 might 'be inserted in pipe line 16, or pump 9might discharge into the pipe 20, thereby lowering the temperatures ofthe liquor passing through the pipes 21, 22, and T 11 to pump 12.

It will be seen that, by passing the liquor through the coil in theheater 14 and letting itescape through nozzle 19 into a furface,containing the hot and dry atmosphere, the liquor is automaticallyblown, exploded or disintegrated into the most minute particles,according to the principles hereinbefore stated. Pipe 19 is formed or Iprovided at its end with a nozzle which is formed with a narrowelongated delivery port so that the explosive actlon plractlcally takesplace at the nozzle. This w ole process, to secure thebest resultscommercially, requires the employment of a Cottrell or electrostatic.recipitator, since the initial velocity ofthe fine particles of liquoris checked almost instantly and the particles more or less float inthefurnace -gases, a

' greater proportion of them being so small and light that they float inthe furnace gases t rough .the boiler and exhauster and would eventuallybe lost in the atmosphere. This. precipitator enables us 'to carry outthis process as it enables us to recover most of the soda in the fineatomized particles which tend to float away. In this connection it maybe observed that the preheating 'ofthe liquor and its disruption asherein stated and the elimination of foreign .fuel

reduces greatly the gas flow: through the boiler tubes and the Cottrellprecipltator.

This is advantageous in that it makes for a more efiicient precipitationof the particles of the soda content and diminishes the loss of heatthrough the furnaces.

In the process above described, it will be seen that the heat, which maybe added to the liquor, is dependent first upon the temperature of thesteam, and, second, upon the pressure, and requires care in the numberof and the selection of the design and speed of the pumps employed. Inorder to over- --'come the ditficulties in pumping this alkaline liquor,we prefer to use high speed high pressure pumps having a lon stufiingbox containing a antern gland. nto this lantern gland oil or'water ispreferably introduced to prevent the caustic liquor from injurin thepacking. Of course in this case the use of brass is not allowable.

Referring again to the drawing, the liquor which 'comes from themanifold 17 through the pipe 20 to pump 21, pipe 22, is pumped through21 (which is used more as a circulating ump than for any other reason),and at the 11 it meets the colder liquor coming from pump 9, so that atthe reduced temperature it passes through pump 12 through the heating.coil where it is raised to the final desired temperature in pipe 16, Inactual practice, the higher the temperaure which can be given to thisliquor the better are .the results secured in the furnace; first,because less heat need be furnished from the furnace proper.to efiectthe evaporation of the water in the liquor, and, second, because of thegreater ex losive effect of the resultin hot liquor. his liquor, when itenters t e furnace, immediately gives up its stored up heat, andliberates a large part of its steam without any extraneous heat, theremaining water being evaporated by the contact of the hot gases withthe particles and by the radiant heat from the walls of the furnace andthe minute burning particles, some of which take fire within a fewinches from the nozzle. The result is that practically all of theparticles, as nearly as can be observed, take fire while in transit, andmany of them have their combustible matter entirely consumed before theyland on the furnace floor. The largest ones, however, may land on thepile 29, which, however, instead of being more or less of a pasty mass,is a live bed of hot combustibles. This breaks off or slumps forwardfrom time to time, and forms a more or less charcoal-like bed throughwhich the. smelted inorganic matter runs to the spout causing thesulfate content to be reduced to sulfide very much the same as if itwere passed through a bed of charcoal.

It will be seen from the foregoing that, first, having supplied a largepart of the heat from an outside source, second, having eliminated theair blast necessary to atomize the liquor, third, causing the burnin ofthe fine atomized particles in transit,.a-n fourth, obtaining more heatfor evaporation by. means of convecti0n,-we have enr ly dispensed withthe necessity of employing a foreign fuel and the air required to burnthe same. W e should, however,'not' regard, it as a departure from theinvention if the ractice of our process were accompanied y thecombustion in the furnace of a seous or other fuel.

n the process and apparatus described therein, and

in the previous Letters Patent, herein referred to, the volume ofcombustible gases was a great deal larger than the volume of thecombustible gases in the present case and consequently caused anincreased flow through the boiler tubes. By cutting down the products ofcombustion, the velocity of the gases and products of combustion throughthe boiler tubes is slower, with the consequent saving of heat, or theprevention of the loss of more heat through the flue gases. Furthermore,as it was not always possible in the previous process and apparatus tomaintain in their entirety the predetermined oxidizing and reducingzones, the large excess of air used to burn the combust1ble gases sometimes acted as an oxidia mg agent in a detrimental oxidation of thesodium sulfid to sulfate.

Summarizin the foregoing, we mix the by means of pumps, heat it whileunder pressurein a heating coil, discharge it into the furnace underpressure, circulate the remainder of the liquor which does not go in thefurnace back to the pumping system, keep the rapid circulation up duringthe whole fprocess and thus prevent precipitation 0 the salt cake, andkeep the pressure up during the Whole operation, to prevent theliberation of steam in the circu lating system. We explode the gasesinto the furnace by the heat internally contained roduceparticles sofine that they lose their moistui e, first, by the heat containedtherein, second, by convection, and, third, by radiation, so that theparticles take fire only a short distance from the not Zles, themselvesfurnishing heat which was formerl obtained from the illuminantsfurni'shed y the foreign fuel. The fine partlcles of valuable mineralcontent, which float away in the gases leaving the furnace, arerecovered in the Cottrell precipitator,

till

and utilized. Preferably a balanced draft .L"

is maintained in the furnace.

While we have in the subsequent cianns defined the invention In thetern-1. a process and apparatus for the treatment of waste liquorresultin. from the digestion of weed in the production of cellulose, itwill be understood that the invention is not necessarily limited to thetreatment of such liquor but is capable of practice in the treatment ofliquid-containing material in which it is desired to evaporate theliquidcontent and consume the combustible content, opuite irre spective of therecovery of any inorganic content, for it will be readily seen that haveprovided, by the present invention, for

cure an effluent rich in sodium sulfid, and,

while this is one of the valuable results of the invention according tothe exemplification thereof herein illustrated and described,

we desire, by no means, to limit the invention thereto. Other liquidandcombustiblecontaining substances than those hereininentioned may beemployed as the starting materials, as will be apparent to personsskilled in the art, and many different kinds of such substances may besubjected to the treatment herein described even though the purpose bemerely to consume'them for the generation of heat or power, or forobviat: ing the necessity of discharging them into rivers or streams, or otherwise disposing ofsaid invention, and described; a way. of making,using andpractising the-same, although without attempting to-set-forth.all of the forms in which it maybe made, all of'the modes of its use,or allof. the ways in which it can be practiced, what we claim is 1 1.The herein described process of treat-1 ing waste liquor which comprisesexploding 1. waste liquor 1n a furnace and subjecting the--disintegratedparticles toheat to cause the evaporation of the liquidcontent,-'and the combustion of the combustible content thereof.

2. The herein described process of treating waste liquor which consistsin subjecting waste liquor to heat while maintainingit under a pressuregreater than its vapor pressureat that temperature to generate an;explosive force therein, liberating the liquor and thereby causing its.disintegration into fine particles, evaporating the'liquid content ofsuch particles, and burning the combustible content of such particles.

3. The herein described process of treating waste liquor which consistsin subject- 'mg waste liquor to high heat and pressure to generate anexplosive force therein, and then liberating the liquor in the presenceof radiant heat to cause the disintegration of the liquor and theevaporation of the liquid content of the resultant particles, andburning the combustible content of such particles.

4.. The herein described process of recovering waste products whichconsists in subjecting waste liquor to heat and pressure to generate anexplosive force therein and liberating the liquor, thereby causing itsdisintegration or disruption 1nto fine particles, evaporating the liquidcontent of such particles, burning the combustible content of suchparticles, and recovering the non-combustible inorganic content of$110.11 particle disintegrated. particles of esa-era 5. The hereindescribed process of treating waste liquor which comprises subjectingwaste liquor to high temperature and pressure, circulating such liquorat high velocity, and liberating a portion thereof in the fire chamberof a furnace-to cause the disruption of such liquor into fine particles,the evaporation of the liquid content and the com bustion of thecombustible content of the particles so liberated. v

.6. The herein described process of treat ing Waste liquor whichcomprises subjecting waste liquor to high temperature while maintainingit at a pressure greater than. its

vaporpressure- .at that. temperature, circulat-- 7ov I ing such liquorat high velocity, then liberat ing a portion of such circulatingliquorina fire chamber-t0- cause the disintegration or a disruption thereof intofine particles by the explosive :force thus generated, and subjectingsuch particles to a high degree of radiant waste liquor at high velocitythrough a heater-and by an explosive force generated thereindisintegrating or disrupting such liquorinto fine particles, andsubjectin the liquor to ra iant and convectedxheat. I

8. The "herein'described process of recovering waste products whichconsists in partially evaporating and concentrating black greaterthanits vapor pressure atthat tem therein and then liberating such blackliquor in a furnace in finely disrupted 'particles, evaporating theliquid content and .perature to generate. an explosive force H burningthe combustible content thereof, and 2 recovering the soda content.

9. The herein described process in thetreatmentiof black liquor whichconsists'in -heating black liquor-to a vaporizing temperature while heldunder a pressure greater than its vapor pressure atsuch temperature togenerate an explosive force therein and liberating such liquor in'aspray of finely disrupted particles, evaporating the liquid content andburning the combustible controstatic precipitation. P

10. The herein'described process oftreating black-liquor which consistsin partially evaporating and concentrating blackliquor, disrupting thesame in a furnace by an explosive force generated in such liquor, andevaporating the liquidcontent thereof by the combustion of thecombustible content git; iike liquor without the'use of a foreign e 1 1The herein described process of treating black liquor which comprisesmixing .tent ofsuch particles and recoverin finely divided particles ofmineral content 1 elec- I finely divided salt cake and black liquor,circulating such mixture at high velocity and at great pressure, heatingsaid mixture to a high temperature to generate an explosive forcetherein, liberatin a portion of said mixture in the fire cham er of afurnace and exposing the particles thereof to radiant and convected heatgenerated by the combustion of previous y liberated liquor in suchchamber.

12. A etc in the process of treating waste liquor whicv consists inatomizing and disrupting the same by an internal disruptive forcegenerated therein.

13. A step in the process of treating waste liquor which consists inatomizing the same by an internal disruptive force generated therein byrelieving the pressure on the liquor after heatin the liquor to a hightemperature while un er a pressure greater than the vapor pressure atthat temperature.

14. The herein described process of treating black liquor which consistsin disrupting black liquor in a heated atmosphere by an internallygenerated explosive force into fine particles, evaporating the liquidcontent thereof and charring the combustible content thereof by radiantheat generated by the combustion of like previously disrupted evaporatedand charred particles.

15. The combination with a furnace and means for evaporatin andconcentrating black liquor, of means %O1 heating such concentratedliquor to a high temperature, means for subjecting such heated liquor togreat pressure to generate an explosive force therein without thegeneration of steam, and

' means for delivering such liquor in a stream or spray to said furnace,whereby when liberated 111 said furnace it explodes into fine particles.

16. The combination with a furnace, of a circulating system for wasteliquor including one or more pumps for subjecting such liquor to greatpressure and a heater for heating the liquor to a high temperaturewithout the generation of steam when under such pressure, and a nozzlefor liberating a stream of said liquor in the fire chamber of suchfurnace.

17. The combination with a furnace, of

means for generating an explosive force-in blfiaclt liquor and explodingsaid liquor into finely disintegrated particles in the fire chamber ofsuch furnace Without the use of an air or steam jet, and burning thecombustible content of such particles.

18. The combination with a furnace, and

means for separating and recovering from the gaseous products ofcombustion soda particles escaping from such furnace, of means forevaporating and concentrating blacl: liquor, means for confining andgen-- erating an explosive or disruptive force in such concentratedblack liquor, means for continuously liberating such blackv liquor intothe fire chamber of such furnace in internally disrupted particles,whereby the heat generated by the combustible content of such particlesevaporates the liquid con tent of the next succeeding particles, .andmeans for recovering the smel-ted soda con.- tent of such particles.

19. The combination With a furnace, of a heater, a circulating systemincluding pumps for circulating black liquor at a high velocityumd greatpressure through said heater and generating an explosive force in saidliquor, means for mixing and delivering a mixture of black liquor andsalt cake to said circulating system, and a nozzle connected to saidcirculating system for delivering said mixture so heated to the fire.chamber of said furnace.

20. The combination With a furnace, of a circulating system for blackliquor comprising conduits, pumps for subjecting said liquor to andforcing it at great pressure and high velocity through said conduits,and a heater for heating it to a high temperature to generate anexplosive force therein, and a nozzle leading from said system into saidfurnace.

21. The combination with a furnace and a nozzle for delivering a streamof black liquor into the fire chamber thereof, of a circulating systemfor such liquor with which, saidnozzle is connected, said systemcomprising conduits, a coil, and one or more umps for circulating andmaintaining the iquor in the conduits and coil under high pressure, andmeans for heating said coil and liquor passing therethrough to a hightemperature while the liquor is at a high pressure, whereby a disruptiveor explosive force is generated therein.

22.-The herein described process of recovering waste products whichcomprises generating an explosive force in and exploding black liquorwithin a furnace, subjecting the disintegrated particles to heat tocause the evaporation of the liquid content and the combustion of thecombustible con; tent thereof, and separating the soda from the wasteproducts of combustion by electro static precipitation.

2-3. The herein described process of recovering waste products whichconsists in subjecting black liquor to heat and pressure to generate adisruptive or explosive force therein, then liberating the liquor topermit .24. The herein described process of recovering waste productswhich comprises generating an explosive force in and explo'ding thefiner particles of the soda, content ing black liquor in the furnace,subjecting from the products of combustion. the disintegrated particlesto heat to cause In testimony whereof We have afiixed our 10 theevaporation of the liquid content and signatur s.

5 the combustion of the combustible content.

thereof, smelting a portion of the soda con- HUGH K. MOORE. tent andrecovering the same, and recover- JQHN T. QUINN.

